Method and apparatus for removing particulate contaminants from commercial laundry waste water

ABSTRACT

A filtration apparatus includes a filter element disposed at a 45 degree angle defining an upper chamber for solids and a lower chamber for liquid. A trough is disposed at the lower end of the filter element. The floor of the trough funnels toward a central drain and an overflow drain is located approximately 8 inches above the trough floor. The lower chamber is provided with a drain for recirculating water to a sprayer above the filter element and is also provided with an overflow drain approximately 8 inches above the floor.

This application is related to co-owned U.S. Pat. No. 5,575,913, thecomplete disclosure of which is hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a filtration apparatus forseparating solid particles from a liquid. More particularly, theinvention relates to filtration apparatus for removing particulatecontaminants from commercial laundry waste water and to methods foraccomplishing the same.

2. State of the Art

State and local governments across the country as well as the federalgovernment have enacted new laws or expanded existing laws to reverse orlimit the threat of environmental pollution. These environmental lawsare typically directed toward commercial enterprises which createvarious wastes streams as a by-product of manufacturing products orproviding services. The commercial laundry industry and particularlycommercial laundromats are specifically affected by environmental lawswhich limit the amount of suspended solids or particulate contaminantsin commercial laundry waste water which can be discharged into theenvironment. Particulate contaminants in commercial laundry waste watergenerally consist of lint, hair, dirt and soap scum. To meet therequirements of current environmental laws, the amount of particulatecontaminants in commercial laundry waste water must be reduced to anacceptable level before it is discharged into the ground water and/ormunicipal sewage system.

Co-owned U.S. Pat. No. 5,350,526 discloses a filtration apparatusspecifically intended for removing particulate contaminants fromcommercial laundry waste water. It has at least one porous mesh-likefilter bag coupled between an inlet manifold for receiving waste watercontaining particulate contaminants and an outlet manifold fordischarging the particulate contaminants separated from the waste water.The filter bag is agitated by a paddle, so as to prevent the mesh-likematerial of the filter bag from being clogged. The apparatus is capableof trapping particles as small as 5 microns depending on the filter bagmesh. Those skilled in the art will appreciate that the finer the meshthe more slowly the water will be filtered. One of the challenges indesigning a filter for commercial laundry waste water is to be able toaccommodate a flow rate of about 12,500 gallons per day.

Co-owned U.S. Pat. No. 5,575,913 discloses a filtration apparatus havinga housing, a filter element, an inlet, a first discharge outlet and asecond discharge outlet. The housing includes a bottom and an upwardlyextending surrounding wall. The filter element is disposed in thehousing and spans the surrounding wall with the filter element spacedabove the bottom of the housing to define an upper chamber and a lowerchamber, and the filter element being angled, preferably 45 degrees fromthe horizontal, so that one end of the filter element is lower relativeto the other end. The inlet is in fluid communication with the upperchamber for receiving waste water containing particulate contaminants. Afirst discharge outlet is in fluid communication with the lower chamberfor discharging filtered waste water. The second discharge outlet is influid communication with the upper chamber adjacent the lower end of thefilter element for discharging filtered particulate contaminants.Particulate contaminants are removed from the filter element by a waterspray. The apparatus is capable of trapping particles about 50 micronsin diameter.

The apparatus disclosed in the '913 patent, while a vast improvementover the prior art, can still be improved. Challenges still remainregarding the build up of solids on the filter element; the removal oflint, hair, and other similar solids from water; water overflow throughthe filter element; hardening of dried solids within the apparatus; thefailure of solids to be drained from the apparatus; and the need forregular human intervention.

SUMMARY OF THE INVENTION

It is an object of the invention to provide an improved filtrationapparatus and method for separating and removing particulatecontaminants from a relatively large continuous flow of laundry wastewater for discharge of the filtered waste water into the environment,i.e., ground water and/or municipal sewage system.

It is another object of the invention to provide such a filtrationapparatus having a filter element for separating particulatecontaminants from laundry waste water in which the separated particulatecontaminants can be easily and quickly manually or automatically removedfrom the apparatus without injuring or removing the filter element.

It is still another object of the invention to provide such a filtrationapparatus wherein hair, lint, sand and other collected solids arequickly and efficiently discharged without manual intervention.

It is yet another object of the invention to provide such a filtrationdevice wherein collected solids are kept in a fluid suspension for easyfluid discharge.

It is also an object of the invention to provide such a filtrationdevice wherein water overflow through the filter element is prevented.

It is another object of the invention to provide such a filtrationdevice wherein water used to spray the filter element is conserved.

It is still yet another object of the present invention to provide sucha filtration apparatus that is easily and inexpensively manufactured;highly efficient in operation, and which requires little lifetimemaintenance.

In accord with these objects which will be discussed in detail below,the filtration apparatus of the present invention includes a housing, afilter element, an inlet, a first discharge outlet and a seconddischarge outlet. The housing includes a bottom and an upwardlyextending surrounding wall. The filter element is disposed in thehousing and spans the surrounding wall with the filter element spacedabove the bottom of the housing to define an upper chamber and a lowerchamber, and the filter element being angled, preferably 45 degrees fromthe horizontal, so that one end of the filter element is lower relativeto the other end. A wall is located at the lower end of the filterelement to provide a trough adjacent to the lower chamber to collectwater with suspended particles. The inlet is in fluid communication withthe upper chamber for receiving waste water containing particulatecontaminants. The first discharge outlet is in fluid communication withthe lower chamber for discharging filtered waste water. The seconddischarge outlet is in fluid communication with the trough fordischarging filtered particulate contaminants suspended in water.Particulate contaminants are removed from the filter element and drainedinto the trough by a water spray located above the filter element.

According to the preferred embodiment, the trough discharge outlet islocated in the middle of the bottom of the trough and the bottom of thetrough is tapered downward to the discharge outlet. An overflowdischarge is also located in the trough to prevent water fromoverflowing above the filter element and floating solids back onto thefilter element. The overflow discharge is preferably terminated with aT-fitting so that water is drained from below the surface. The lowerchamber is also provided with a second discharge for recycling filteredwater to the spraying system.

The filtration unit according to the invention has the capacity tofilter larger volume of water more efficiently, and requires little orNO human physical participation. The addition of the trough creates afilter system with its own solid waste storage capabilities. Thiscreates longer filter runs without the need for manual or electricallytimed discharge, this means less energy used and less manual attentionto the unit.

The filter screen is never compromised with the collected solids on themesh screen itself Thus the filter screen is always free from solids.This allows the filter the ability to handle a continuous higher volumeand will always remain at its maximum use and potential.

The unit will also supply itself with its own feed water for the actionof spraying down the screen.

Additional objects and advantages of the invention will become apparentto those skilled in the art upon reference to the detailed descriptiontaken in conjunction with the provided figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentarily-illustrated perspective view of the filtrationapparatus embodying the present invention with portions broken away toshow internal construction;

FIG. 2 is a fragmentarily-illustrated side view of the filtrationapparatus shown in FIG. 1;

FIG. 3 is a schematic side elevation view of the overflow drain; and

FIG. 4 is a schematic side elevation view of the relative locations ofthe four discharge outlets of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, and in particular to FIG. 1, a filtrationapparatus 10 according to the invention receives laundry waste waterdischarge from a number of commercial laundry washing machines via pipe100. The filtration apparatus 10 generally includes a housing 20, afilter element 40, a laundry waste water inlet having an open top end64, a filtered waste water discharge outlet 62, particulate contaminateoutlet 60 and a sprayer 70.

The housing 20 includes a bottom 22 and an upwardly extendingsurrounding wall 24. Specifically, housing 20 has a generally openbox-like configuration in which bottom 22 is rectangularly shaped andupwardly extending side wall 24 consists of a front wall 25, a rear wall26 and two side walls 27. It is appreciated that the bottom 22 ofhousing 20 can be circularly or squarely shaped. Preferably, housing 22is fabricated from a rust resistant material such as a plastic material.

The filter element 40 is disposed in the interior of housing 20,spanning between the interior surface of surrounding wall 24. Generally,the filter element 40 consists of an interwoven filtering material 42,preferably a micro screen such as a monofilament mesh fabricated fromnylon, and a surrounding frame 44. The frame 44 provides a border aroundinterwoven filtering material 42 and which serves as structural supportfor interwoven filtering material 42. Such factors as the amount andconsistency of the laundry waste water flow rate, and size and amount ofsolid particulate contaminants, etc. will dictate the desired mesh sizeof the interwoven filtering material 42. Desirably, the interwovenfiltering material 42 has a mesh size ranging from about 70 microns to25 microns. Preferably, the frame 44 is fabricated from a rust resistantmetal such as aluminum.

The housing 20 includes a support 30 attached to the interior surface ofsurrounding wall 24 for providing support to filter element 40.Specifically, the support 30 includes a lower front support 35, an upperrear support 36, and two side supports 37 which are angled from lowerfront support 35 to the upper rear support 36. Preferably, the support30 includes a continuous rubber material which forms a seal with frame44 of the filter element 40 so that, as explained below, particulatecontaminants will not pass around frame 44 but will be retained oninterwoven filtering material 42.

Preferably, the housing 20 includes a plurality of releasable lockingmeans 47 for releasably locking the frame 44 of the filter element 40 ina fixed position in the housing 20. The releasable locking means 47 maycomprise pivotable latch-like arms mounted on each of the sidewalls 25,26 and 27 for movement between a release position (shown in phantom inFIG. 1) and a locking position with respect to the frame 44. In thelatter position, it either closely abuts the frame 44 or is receivedwithin a corresponding slot 51 in frame 44.

The filter element 40 is disposed within the interior of housing 20 andspaced apart from bottom 22 forming an upper chamber 50 (unfilteredspace) and a lower chamber 52 (filtered space). The filter element 40 isangled so that a lower end 46 is lower relative to an upper end 48.Preferably, the filter element 40 is angled at between about 30 degreesand 60 degrees from the horizontal. Most preferably, filter element 40is angled at about 45 degrees from the horizontal.

The upper edge 28 of the surrounding wall 24 forms waste water inlet 64,in fluid communication with upper chamber 50, for receiving laundrywaste water containing particulate contaminants from discharge pipe 100.It will be appreciated that the housing 20 can include a cover or lidsupported on upper edge 28 of surrounding wall 24 and provided with ainlet opening for receiving laundry waste water containing particulatecontaminants.

A filtered waste water discharge outlet 62, in fluid communication withlower chamber 52, provides for discharge of collected filtered wastewater in lower chamber 52. Filtered waste water discharge outlet 62 canbe positioned over a floor drain or connected to a conduit for dischargeof the collected filtered waste water into the ground water and/ormunicipal sewage system. According to one aspect of the invention, andas seen best in FIGS. 2 and 4, the filtered waste water discharge outlet62 extends upward from the bottom 22 of housing 20 for about eightinches. This creates a reservoir of filtered water 113 inside thechamber 52. A drain 71 is located approximately one inch from the floor22 of the chamber 52. The drain 71 provides access to the reservoir offiltered water which may be recycled to the sprayer 70 with the aid of apump (not shown).

According to another aspect of the invention, a wall 49 seen best inFIGS. 2 and 4, is disposed parallel to the front wall 25 between thefloor 22 and the bottom end 46 of the filter element to create a troughseparated from the lower chamber 52. The particulate contaminatedischarge outlet 60, in fluid communication with the trough of the upperchamber 50, is preferably centrally located. As seen best in FIG. 1, thefloor 29 of the trough preferably funnels toward the centrally locateddischarge 60.

According to yet another aspect of the invention, a particulatecontaminate discharge overflow outlet 61 is disposed in side wall 27adjacent lower end 46 of filter element 40. As seen best in FIG. 3, theoutlet 61 terminates in a T-fitting 21 so that liquid is discharged frombelow the surface 110 of the waste water 111 and the collected film ofsolid waste 112 (see arrow) and recycled back to the waste water inletpipe 100 via a pump (not shown).

As seen in FIGS. 1 and 2, spray means 70 for discharging a spray ofliquid, preferably water under pressure from a suitable source (notshown), across an upper surface 45 of filter element 40 flushes orcauses particulate contaminants collected on upper surface 45 of filterelement 40 to move toward lower end 46 into the trough and towardparticulate contaminate discharge outlet 60. Specifically, the spraymeans 70 includes a pair of pipes 72 each extending horizontally alongthe interior of housing above filter element 40. Extending from eachpipe 72 are L-shaped pipes 74 having a pair of nozzles 76. In addition,nozzles 78 are attached at each end of pipe 72. Preferably, pipes 72 andL-shaped pipes 74 are fabricated from a plastic material such aspolyvinyl chloride (PVC). It will be appreciated that one skilled in theart could provide other equally suitable alternative configurations forpositioning the spray nozzles above filter element 40 to causeaccumulated particulate contaminants on upper surface 45 of filterelement 40 to move toward lower end 46 and toward particulatecontaminate discharge outlet 60.

Spray means 70, as explained below, can be operated to prohibitparticulate contaminants from accumulating on upper surface 45 of filterelement 40 and clogging the interwoven filtering material 42 of filterelement 40 by either constantly supplying a spray of liquid duringoperation or alternatively at periodic intervals. Removal of particulatecontaminants from filtering apparatus 10 can be accomplished manually orpreferably by coordination of spray means 70 and a discharge valve 80.Specifically, discharge valve 80 is in fluid communication withparticulate contaminate discharge outlet 60 and is normally closed sothat laundry waste water is not carried out particulate contaminatedischarge outlet 60 during operation. When the filter element 40 has andexcessive amount of accumulated particulate contaminants thereon, thedischarge valve 80 can be opened and the accumulated particulatecontaminants can be flushed out by activation of spray means 70.Preferably, discharge valve 80 is operated by a conventional solenoid 82connected by an electrical wire or lead 84 to a conventional timer 86for automatic periodic flushing and discharge of the collectedparticulate contaminants in conjunction with spray means 70 byconcurrent control of valve 92 operated by solenoid 96 also connectedvia wire 94 or the like to timer 86, the latter of which would beconnected to an electrical outlet. As mentioned above, water for thesprayer 70 is preferably obtained from outlet 71 provided in the lowerchamber 52.

The operation of the present invention will be understood as follows:laundry waste water from washing machines is introduced into thefiltration apparatus 10 by laundry waste water discharge tube 100 asshown by the solid arrow in FIG. 1. The laundry waste water is depositedon upper end 48 of upper surface 45 of filter element 40. Filtered wastewater, shown as dashed arrows in FIG. 2, passes through the filterelement 40 while particulate contaminants accumulate on upper surface 45of the filter element 40.

The unique design of filtering system 10 takes advantage ofgravitational forces, and hydraulic forces from subsequent discharge oflaundry waste water to naturally cause accumulated particulatecontaminants on upper surface 45 of filter element 40 to move downwardalong upper surface 45 toward lower end 46 and into the trough definedby wall 49. In addition, spray means 70 can be operated continuously orperiodically to aid in causing accumulated particulate contaminants onupper surface 45 of filter element 40 to move downward along the uppersurface toward lower end 46 and into the trough.

Removal of particulate contaminants from upper chamber 52 of housing 20may be accomplished manually or preferably by coordination of spraymeans 70 and discharge valve 80. Specifically, spray means 70 isoperated to supply a spray of liquid continuously during operation or atperiodic intervals in coordination with discharge valve 80. Dischargevalve 80 is attached to particulate contaminate discharge outlet 60 andis normally closed (unless continuous spraying is used) so that wastewater is not carried out particulate contaminate discharge outlet 60during normal filtering operation. When the trough and filter element 40fills up with excessive particulate contaminants, discharge valve 80 canbe opened and the accumulated retained particulate contaminants can beflushed out. Preferably, as indicated above, water supply valve 92 anddischarge valve 80 are operated by conventional solenoids 82, 96,respectively, connected by wires 84, 94, respectively, to a conventionaltimer 86 for concurrent operation and automatic periodic flushing anddischarge of the collected particulate contaminants. As mentioned above,the overflow drain 61 recirculates partially filtered waste water to theinlet of the filtration apparatus.

Various modifications can be made as will be apparent to those skilledin the art. For example, while only one row of pipes 74 and nozzles 76are shown, two or more may be provided to facilitate contaminantdischarge and cleaning of the filter or screen 40. However, the variousparts shown in the drawing are commercially available so that the unitcan be made economically.

Furthermore, although only one unit is shown in the drawings, multipleunits could be employed in series having differently- anddecreasingly-sized screen mesh openings to achieved a tiered screeningeffect.

The improvements provided by the present invention can be summarized inpart as follows: the location of the wall 49 to define the trough, thelocation of the drain 60 in the center of the trough, the funnelling ofthe floor 29 of the trough, the provision of the T-drain 21/61 in thetrough, the location of the raised drain 62 in the chamber 52 to providea reservoir of filtered water, and the location of the drain 71 fortapping the reservoir. It will be appreciated that many of theseimprovements may be used either alone or in combination with each other.

It will therefore be appreciated by those skilled in the art that yetother modifications could be made to the provided invention withoutdeviating from its spirit and scope as so claimed.

What is claimed is:
 1. A filtration apparatus for filtering waste watercontaining particulate contaminants, said apparatus comprising: a) ahousing having a bottom and an upwardly extending surrounding wall, andan inlet for receiving waste water containing particulate contaminants;b) a substantially planar filter element having an interwoven filteringmaterial, said filter element being disposed in said housing and atleast partially spanning said surrounding wall, said filter elementbeing spaced between said bottom and said inlet of said housing at anangle thereby defining an upper end and a lower end of said filterelement; c) a dividing wall extending from the lower end of said filterelement to said bottom of said housing thereby defining an unfilteredwater space and a filtered water space; d) a first discharge outlet influid communication with said filtered water space for dischargingfiltered waste water; e) a second discharge outlet in fluidcommunication with said unfiltered water space for dischargingparticulate contaminants; and f) an overflow outlet in said unfilteredwater space having a T-fitting inlet.
 2. An apparatus according to claim1, wherein: said second discharge outlet is centrally located in saidunfiltered water space and said bottom of said housing funnels towardsaid second discharge outlet in said unfiltered water space.
 3. Anapparatus according to claim 1, wherein: said first discharge outletincludes an upstanding pipe rising from said bottom of said housing insaid filtered water space, thereby creating a reservoir for filteredwater.
 4. An apparatus according to claim 3, further comprising: f) areservoir access outlet in fluid communication with said reservoir offiltered water.
 5. A filtration apparatus for filtering waste watercontaining particulate contaminants, said apparatus comprising: a) ahousing having a bottom and an upwardly extending surrounding wall, andan inlet for receiving waste water containing particulate contaminants;b) a substantially planar filter element having an interwoven filteringmaterial and an end, said filter element being disposed in said housingand at least partially spanning said surrounding wall, said filterelement being spaced between said bottom and said inlet of said housingthereby defining an upper unfiltered water space and a lower filteredwater space; (c) a dividing wall extending from said end of said filterelement to said bottom of said housing thereby defining an unfilteredwater space and a filtered water space; (d) a first discharge outlet influid communication with said lower filtered water space for dischargingfiltered waste water, wherein said first discharge outlet including anupstanding pipe rising from said bottom of said housing in said filteredwater space, thereby creating a reservoir for filtered water; (e) asecond discharge outlet in fluid communication with said unfilteredwater space for discharging particulate contaminants; and (f) anoverflow outlet in said unfiltered water space having a T-fitting inlet.6. An apparatus according to claim 5, further comprising: (g) areservoir access outlet in fluid communication with said reservoir offiltered water.